I would just go sponge filters or HOB, cannister filters myself. If those slots are so small that a shrimp can't fit through, they are small enough to get clogged fairly regularly. Baby shrimp are very small for the first few weeks, so much that you can't even usually see them without a magnifying glass.
Your choice, give them a show if you want, I think they may be too big myself.
20g platy, , 2 x 10g shrimp, 3 x 20g shrimp, 7.5g shrimp and 1 great dane/mastiff puppy.
Sump Pimp #2
My Tanks and my shrimps